Fishing tool



P. 'M. REA

.FISHING TOOL Oct. 15, 1940.

Filed July 51, 1929 ZShets-Shet 1 1 Oct. 15, 1940.

P. M. REA

FISHING TOOL I Filed July 51, 1939 2 Sheets-Sheet 2 Am i lallflllltPatented Oct. 15, 1940 UNITED STATE PATENT QFFICE FISHING TOOL Philip M.Rea, Oklahoma City, Okla.

Application July 31, 1939, Serial No. 287,567

8 Claims.

My invention relates to tools for removing cylindrical objects, such asdrill pipe, tubing, and the like, from wells, and more particularly tofis ing tools of the type commonly known in the art as an overshot.

It has at the present time become customary in oil well drilling to use5% drill stem in well casing having an inside diameter of 8 Since thetool joint of the 55+," drill stem has an outside diameter of 7", thereis an annular space of only of 1%", or it wide around the tool joint.When it is considered that there must be at least a working clearancebetween the outside diameter of the overshot bowl and the insidediameter of the casing, this confines the combined thickness of the bowland slips to be not over inches. In oil well fishing it is frequentlynecessary to exert a pull on the fish of as much as one hundred tons,and to do this with a tool having only wall thickness is a considerableproblem.

It is the prime object of the present invention to provide an overshotfishing tool which will function within the limited annular spaceavailable in present oil well drilling, and which will operatesuccessfully in lifting the required loads. The present device, made inaccordance with the stipulated diameters, has been tested and with--stood a pull of 200 tons before the bowl was sufficiently distorted topermit the slips to slide past their seating surfaces. It is believedthat this is the greatest pull ever exerted upon a slip type overshotwith a wall thickness of only e;- of an inch. The slips were only 3 3 ofan inch thick.

Another object of the invention is to provide a thin walled overshot inwhich the outward thrust of the load is so distributed that distortionof the bowl is reduced to a minimum.

A still further object is to render the overshot releasable from thefish.

Another object is to make circulation of a fluid through the bowl andfish possible.

Other objects of the invention are: to insure positive engagement of thefish by the slips; to provide a tool of this class which is simple inconstruction; the parts of which may be easily and quickly assembled, orremoved for replacement; which is durable; and, which is efficient inaccomplishing all of the purposes for which it is intended.

In the drawings:

Figure l is an elevational View of the tool operatively disposed withina section of well casing;

Figure 2 is a vertical sectional view of the overshot bowl with a fishengaged by the slips thereof;

Figure 3 is a horizontal sectional view taken substantially along theline 3-3 of Fig. 2;

Figure 4 is a vertical sectional view of the bowl with the slips thereinshown in perspective, the section having been taken substantially alongthe line 3-4 of Fig. 3;

Figure 5 is a vertical sectional view of the bowl per se, the slipshaving been removed, said section having been taken substantially alongthe line 55 of Fig. 3; and,

Figure 6 is a perspective view of one of the slip segments.

Like. characters of reference designate like parts in all of thefigures.

A preferred embodiment of the invention is illustrated in theaccompanying two-sheet drawings wherein:

The reference numeral I indicates a typical well casing in which isdisposed a fish 2. In this instance, the fish is shown as being the endof a drill stem section, the drill stem having presumably parted at thejoint, leaving the lower portion of the string in the hole. Thereference numeral 3 indicates the narrow annular space within which thetool is designed to function. i indicates thelower end of a fishingstring which is adapted to be threaded into threads 5 in the upper endof a suitable tubular sub 6. The parts thus far described are usual andare not a part of the invention per se. The invention includes and isembodied within a tubular bowl ill having its upper end interiorlythreaded at H to engage the lower end of the sub 6.

The bowl l8 has a bore l2 extending from its upper end downwardly toadjacent its lower end Where it is tapered inwardly to form a slip seatl3. Below the slip seat E3, the bore of the bowl is cylindrical. Thisportion of the bowl is cylindrical. This portion of the bowl isindicated by the reference numeral M. The lower end of the bowl I6 isexteriorly threaded at [5 to receive the upper end of a tubular guideshoe IS. The shoe it may be of any usual form for guiding the fish intothe bowl, for instance, it may be a usual milling tool, wall hook, orthe like.

The slip seat i3 is not continuously annular, but is divided into fourradially spaced seats which are formed by keys I! made integrally withthe inner wall of the bowl Ill and extending above the slip seat it. Thefour radially spaced inwardly projecting keys I! have their upper endsinwardly and downwardly tapered to form additional or auxiliary slipseating surfaces l8, and, as is apparent in Fig. 5, the seating surfaces28 are radially staggered with relation to the slip seats IS.

A pair of identical slip segments l9 and 20 are provided for seatingupon the slip seats l3 and I8, and their operative positions are bestshown in Fig. 4. The element i9 is set apart and is detailed in Fig. 6,and consists substantially of a semi-circular sleeve having dependingradially spaced legs 2| adapted to fit within the interstices betweenthe keys I! of the bowl, and each leg having a tapered lower end portion22 adapted to register with and seat upon the spaced slip seats I3 ofthe bowl. Intermediate the legs 2|, the slip segments l9 and 210 eachhave tapered outer surfaces 23 adapted to register with and seat uponthe seating surfaces E8 on the upper ends of the keys H. The meetingsurfaces or edges of the slip segments l9 and 20 are preferablycomplementally step-cut as shown at 26 so that when they are inoperative position within the bowl, they must move in unison. The innersurfaces of the slip segments I9 and 20 are provided with continuouscomplemental threads 25 so that they may be unscrewed from the fish ifdesired. The slip segments are installed within the bowl ID by merelydropping them into place upon the seats l3 and i8.

Above the slips and within the bowl i0, is provided a resilient annularsealing element 26 adapted to seal between the bowl and the fish 2. Theelement 26 is urged into contact with the upper ends of the slipsegments by a tubular follower 21 and a compression spring 28. The lowerend of the body section 6 acts to maintain the spring 28 undercompression.

Obviously, the action of the spring acts to force the slip segmentsdownwardly upon their seats so that they will immediately engage a fishupon its insertion into the slips.

In operation, as the bowl is lowered over the fish 2, the slip segmentsl9 and 2t are moved upwardly, by contact with the fish, a sufficientdistance against the action of the spring 28 to permit their lateralmovement away from each other, thus permitting entry of the fish intothe slips. When the bowl is subsequently raised by upward movement ofthe string l, the slips move slightly downwardly upon theirseats l3 andi8 and are forced thereby into frictional engagement with the fish.

Since the slips are made of a material which is harder than the fish,the threads 25 cut into the exterior surface of the fish. Should it thenbe found desirable to release the fish, the bowl may be loweredsufficiently to relieve the wedging action of the slip seats, androtation of the bowl will then act to unscrew the slips from the fish.The keys I! and legs 2|, of course, cause the slips to rotate with thebowl.

It is pointed out that since the keys I! are part of the bowl and alsoact as seats, and since the slip segments have the two tapered surfaces22 and 23, there is no occasion to use an auxiliary key to preventrotation of the slips with relation to the bowl. Consequently, neitherthe slips nor the bowl is weakened by providing for a key arrangement asis necessary with usual releasing overshots. Also, there are twovertically spaced seats each having substantially 360 degrees of seatingcontact. This arrangement permits both the bowl and slips to be madestronger than usual overshots designed to operate in an annular space oflike dimensions.

Obviously more than one set of slips may be embodied in a single bowl,if desired.

The sealing element 26 renders it possible to obtain fluid circulationthrough the fish in order to assist in loosening it from the well.

I claim:

1. In an overshot fishing tool: a tubular bowl; a set of radially spacedtapered slip seating surfaces in the bore of the bowl; a second set ofradially spaced tapered slip seating surfaces in the bowl beneath thefirst set, said second set being staggered radially with relation to thefirst set; and, a set of segmental pipe slips removably disposed withinsaid bowl and having tapered surfaces corresponding to and adapted toseat upon both of said sets of slip seating surfaces.

2. In an overshot fishing tool: a tubular bowl; a set of radially spacedtapered slip seating surfaces in the bore of the bowl; a second set ofradially spaced tapered slip seating surfaces in the bowl beneath thefirst set, said second set being staggered radially with relation to thefirst set; and, a set of interiorly threaded segmental pipe slipsremovably disposed within said bowl and having tapered surfacescorresponding to and adapted to seat upon both of said sets of slipseating surfaces.

3. Organization as described in claim 1, in which the meeting edges ofthe slip segments intermesh to prevent their independent longitudinalmovement.

4. Organization as described in claim 1, in which each slip segmentcomprises: an upper body arcuate in cross-section and having exteriorradially spaced tapered seating surfaces; radially spaced legs extendingdownwardly from said body and located between the seating surfacesthereof; and, an exterior tapered seating surface carried by each ofsaid legs.

5. Organization as described in claim 1, in which each slip segmentcomprises: an upper body arcuate in cross-section and having exteriorradially spaced tapered seating surfaces at its lower end; radiallyspaced legs extending downwardly from saidbody and located between theseating surfaces thereof; and, an exterior tapered seating surfacecarried by the lower end of each of said legs.

6. Organization as described in claim 1, in which each slip segmentcomprises: an upper body arcuate in cross-section and having exteriorradially spaced tapered seating surfaces; radially spaced legs extendingdownwardly from said body and located between the seating surfacesthereof: and, an exterior tapered seating surface carried by each ofsaid legs, the side edges of said legs acting to prevent independentrotation of the slip segments in the bowl, by co-action with the sideedges of the vertically extending portions of the bowl which lie betweenits sets of slip seating surfaces.

7. An overshot fishing tool including: a tubular bowl; a series ofradially spaced tapered slip seat'mg surfaces in the bore of the bowl; asecond series of similar slip seating surfaces in said bowl beneath thefirst series and radially staggered with relation thereto; and, a set ofsegmental slips having seating surfaces for seating upon both series ofseating surfaces in said bowl.

8. An overshot fishing tool including: a set of segmental pipe slipseach segment of which comprises an upper body arcuate in cross-sectionand having exterior radially spaced tapered seating surfaces; radiallyspaced legs extending downwardly from said body and located between theseating surfaces thereof; an exterior tapered seating surface carried byeach leg; and, a tubular bowl for receiving said slips, the bore of saidbowl having tapered slip seating surfaces for contacting and seating allof the seating surfaces of said slips.

PHILIP M. REA.

